By calculating the amount of time between when the sound wave was sent and when it bounced back, it measures the distance and shows it on the screen. If the wave doesn’t encounter anything on its way, it reaches the bottom. If the bottom is soft and it’s just mud and weeds, the signal gets absorbed. A rock bottom will reflect a stronger signal back.
Commercial and naval fathometers of yesteryear used a strip chart recorder where an advancing roll of paper was marked by a stylus to make a permanent copy of the depth, usually with some means of also recording time (Each mark or time 'tic' is proportional to distance traveled) so that the strip charts could be readily compared to navigation charts and maneuvering logs (speed changes). Much of the world's ocean depths have been mapped using such recording strips. Fathometers of this type usually offered multiple (chart advance) speed settings, and sometimes, multiple frequencies as well. (Deep Ocean—Low Frequency carries better, Shallows—high frequency shows smaller structures (like fish, submerged reefs, wrecks, or other bottom composition features of interest.) At high frequency settings, high chart speeds, such fathometers give a picture of the bottom and any intervening large or schooling fish that can be related to position. Fathometers of the constant recording type are still mandated for all large vessels (100+ tons displacement) in restricted waters (i.e. generally, within 15 miles (24 km) of land).

When compared to other finders, this screen is relatively small, but it still gets the job done. Since it’s in full color and has high contrast, you can still see everything quite clearly. The only downside is that you have to switch between menus, which can be a problem if you are trying to find fish and mark your location. Overall, it’s not necessarily a deal breaker, but it may be enough to warrant a larger screen. Fortunately, the Striker can come in bigger sizes if you want to upgrade.

You want to turn the fish finder on. It will be set in automatic mode already, with the pre-program settings already on. You can switch it to a manual mode at any time to customized the finder. When you first turn it on, you can leave it in the automatic mode. You then want to drive on the water in automatic mode to get an idea of what it’s seeing.
Fishfinders allow anglers to see a graphic representation of what is beneath their boats so they can identify fish. To choose a fishfinder, consider the type of unit—whether it includes GPS and is part of a boatwide network, size of the fishfinder’s footprint, resolution of the display, how much transmitting power you need, and what frequencies will work best in the inland, coastal or deep-water environment where you fish.
The use of the hook in angling is descended, historically, from what would today be called a "gorge". The word "gorge", in this context, comes from an archaic word meaning "throat". Gorges were used by ancient peoples to capture fish. A gorge was a long, thin piece of bone or stone attached by its midpoint to a thin line. The gorge would be fixed with a bait so that it would rest parallel to the lay of the line. When a fish swallowed the bait, a tug on the line caused the gorge to orient itself at right angles to the line, thereby sticking in the fish's gullet.
The intensity of the sonar return from a hard bottom will be different to one from a hard bottom. Your fish finder uses colour to show this difference. In the standard colour palette of the Deeper display, the colour varies from dull brown (softest) to intense orange (hardest). In the day mode colour palette (see screen shot), the difference is even easier to see, with the colour ranging from purple (softest) to red to orange to yellow (hardest).
Pinpoint your favorite waypoints and track fish with a fishfinder from Academy Sports + Outdoors. With a detailed black-and white LCD display, you can clearly spot fish as deep as 1,000' as well as track their location with depth finder technology. Water temperature sensors allow you to monitor the biological patterns of prospective catches, letting you pinpoint where they'll be at any time of day. With a waterproof casing, our selection of fishfinders are designed for use on boats or kayaks. Our giant boating and marine shop has an assortment of marine electronics from popular brands, like Humminbird, Garmin marine and Lowrance, can help you reel in the largest catch. Receive notifications for certain depths and types of fish, as well as sonar and mapping software, so you can find exactly what you're looking for.
While many fish finders point directly underneath your boat, higher end units like this one will sweep to the sides as well. Considering that you are casting out from the ship rather than dangling lines beneath it, side sweeping is much more valuable as it allows you to find fish wherever you are, rather than finding them, moving the boat, and then trying to catch them.

Networked system: Fully networked systems are available from all the major suppliers, and usually will support a huge range of data sources including radar, raster and vector GPS charts, video, and SiriusXM satellite radio. Many allow Bluetooth/WiFi, and you can control them from your iPhone or Android smartphone. Your fishfinder, often an external “black box” module, is just one of these sources of data. Multiple-display network systems are great for medium-sized or large vessels. Capabilities get more amazing every year.
These sonar reflections will also display on the screen. So this way a fishfinder reads and lets you view the bottom and everything it encounters in between. The angle of the sonar beam is measured in degrees and it’s called the cone angle. A wider angle covers more area underwater. Different fish detector models come with different cone angles. Some models also include multi-beam sonar technology that allows covering a much wider area.
The term tackle, with the meaning "apparatus for fishing", has been in use from 1398 AD.[1] Fishing tackle is also called fishing gear. However the term fishing gear is more usually used in the context of commercial fishing, whereas fishing tackle is more often used in the context of recreational fishing. This article covers equipment used by recreational anglers.